Interpretive Summary: This research gathered field data on sulfur in the atmosphere near Nebraska feedlots. Observations were compared with current regulatory thresholds for Nebraska. An attempt was made to identify factors that influence these levels. Observations were made on three Nebraska feedlots during spring, summer, and fall conditions. Peak levels were detected during mid-afternoon, probably due to increased soil temperatures. Wet feedlot surface conditions did not appear to increase levels. Based on these observations, sulfur levels in the vicinity of beef cattle feedlots are not likely to exceed Nebraska regulatory thresholds.

Technical Abstract:
A survey study was conducted to gather preliminary field data as to the level of Total Reduced Sulfurs (TRS) in the vicinity of typical Nebraska feedlots, compare those observations against current regulatory thresholds for Nebraska, and identify environmental factors that influence TRS levels. Levels of TRS were observed on three Nebraska feedlots for a one-week period during typical spring, summer, and fall conditions. Measurements were made at the feedlot perimeter and at all three locations within the feedlot. An additional survey at the center of one feedlot was conducted for 10 weeks during the spring of 2001. Based on these observations it was concluded that TRS levels in the vicinity of beef cattle feedlots are unlikely to exceed Nebraska regulatory thresholds. Levels of TRS increase linearly with increasing air temperature and a diurnal pattern was observed for TRS levels which peaked in mid-afternoon. This pattern is likely attributable to feedlot surface temperature and possibly animal traffic. Wet feedlot surface conditions, however, did not appear to increase TRS levels.